R-Squared Energy TV: Episode 8 – Biomass Pros and Cons

In this week’s episode of R-Squared Energy TV, I give a short presentation on the pros and cons of using biomass for energy. People tend to have strong feelings on this topic in one way or another, and I will explore a bit of the reason for the controversy.

Some of the topics discussed are:

Can energy from biomass replace oil?

Can energy from biomass be sustainable?

What are the risks of using biomass for energy?

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Thanks again for another episode. It always seemed to me our energy use by burning fossil fuels far outstrips the energy that can be had by growing biomass, but it was interesting to learn somebody spent time trying to calculate by how much. In that context humans are greedy in their energy use.

You brought up corn ethanol as being more renewable if the distillation wasn’t fueled by NG, but there wasn’t mention about the need of ammonia based fertilizers, which has the fossil fuel input of NG, to grow that corn.

Is renewable corn based ethanol possible when considering the fertilizer input?

You could suck carbon out of the air with trees, but not if you turn around and burn them again. If, after you burn trees, it takes decades to regrow, then their carbon stays in the air for decades.

But when you are using trees for energy in a sustainable manner, you are rotating your harvest from one area to another and replanting. So you always have trees in various stages of growth. The point about sucking the carbon out of the air is that most of the biomass is not coming out of the soil — not that there is any long-term CO2 sequestration implied.

The other point is that when using trees for energy, it is optimal to harvest them on a 7 to 10 year cycle. After that, their growth slows.

Is renewable corn based ethanol possible when considering the fertilizer input?

I presume you meant impossible? If you are using fossil fuel-based fertilizer, then that clearly isn’t renewable. But there are ways to produce corn sustainably by recycling the nutrients. It isn’t as profitable, and it will be more labor intensive, but it is doable. Imagine that the distiller’s dried grains were all recycled back to the soil instead of being sold for animal feed. You would be putting nutrients back into the soil, but the DDGS is worth more as animal feed than it would be as fertilizer. So we make certain unsustainable choices because of economics, but those aren’t the only choices to be made.

Natural gas prices may drop below $2/million btu this summer, while gasoline and diesel climb above $4.50/gallon. Any chance that this widening price spread might get some interest going for building GtL plants in North America?

You would be putting nutrients back into the soil, but the DDGS is worth more as animal feed than it would be as fertilizer.

That’s inside the box thinking: the big source of fertilizer is wastewater, especially in large cities. At the moment we use fossil fuels to convert molecular nitrogen (from air) into ammonia. And on the other end, we use fossil fuels (delivered as electricity) to convert left-over ammonia into nitrogen. There’s an obvious opportunity their, and companies like Ostara are just starting to get going.

Once again, we need more expensive crude for these kinds of technologies to be financially attractive…

Natural gas prices may drop below $2/million btu this summer, while gasoline and diesel climb above $4.50/gallon. Any chance that this widening price spread might get some interest going for building GtL plants in North America?

Because of the enormous capital costs, the only way that this spread could justify building GTL plants is if someone could lock in those prices (and a long-term supply). One of the things I can recall from my days at ConocoPhillips was that the economics hinged upon something like 25 years of natural gas supply, and a good spread between natural gas and diesel.

Off topic, but thanks for the following comments on the Oil Drum, ‘as you were recently soliciting comments for your up-coming book. A contributor said::

“The primary solution will be Electric Vehicles, either in the form of electric rail for freight, or personal EVs (probably with liquid fueled range extender generators on board to provide the 10% of miles that are long-range, as with the Volt).”
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Robert’s response:

“That is my belief as well, that if there is a solution that allows us mobility similar to what we enjoy today, it will primarily involve solar power and electric transport.”

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Thank you Robert. I think we are on the same page.

Of course, questions remain: Will solar ever get there ? I think the overwhelming answer is yes……… Let’s look at what happened with television.

The first patents for television were filed way back in 1927-28 by Farhnsworth. That’s a long time ago. It took 83 years of hard work and innovation to bring us to mass production and adoption of the LCD and plasma flat screen technologies we enjoy today.
Television —- nearly a Century in development. Amazing…

On the other hand, Solar has basically only been around since 1956 with the first Bell Labs patents, (about 54 years). If you compare the “progress” of television over 84 years, then, just to be fair, let’s give solar another 30 years of development and see where it end up. Patience…my friends, solar will get there.

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On the related subject, the electrification of transportation, I also agree. How are we are going to put yet another One Billion ICE vehicles on the road with all the geological and geopolitical dead ends of OIL. ?

But when you are using trees for energy in a sustainable manner, you are rotating your harvest from one area to another and replanting. So you always have trees in various stages of growth.

Right …it becomes a related rates problem. You must plant seedlings to pull carbon out of the air as fast as burning mature trees are putting it into the air. Burning a ten year old tree puts its carbon into the atmosphere. The carbon is doing damage (helping to heat the planet) for all of the years it takes a single seedling, or thousands of seedlings, to replace it.

Would the number of trees burned be limited by the amount of carbon being captured by maturing trees?

And how would that be mandated, regulated, and who would keep the carbon books (which we all know would be cooked).

In addition, most GHG abatement plans hope to get carbon back out of the atmosphere, not just reduce how much is being added. Forests that are allowed to remain permanently uncut are the main way to do that.

I suspect that converting biomass into energy is an idea that, if allowed to scale, will do more damage than fossil fuels per unit energy delivered.

Add in complexities like land use change and ecosystem protection. An intact grassland, wetland, or forest ecosystem should not be confused with a hayfield, water reservoir or tree farm respectively. A tree farm is about as biologically diverse as a corn field, which is one species away from being as biologically diverse as a parking lot.

But when you are using trees for energy in a sustainable manner, you are rotating your harvest from one area to another and replanting. So you always have trees in various stages of growth.

Right …it becomes a related rates problem. You must plant seedlings to pull carbon out of the air as fast as burning mature trees are putting it into the air. Burning a ten year old tree puts its carbon into the atmosphere. The carbon is doing damage (helping to heat the planet) for all of the years it takes a single seedling, or thousands of seedlings, to replace it.

This is how it works in practice. I have a forest that I will use to feed a BTL plant. Each year I harvest and replant 1/10th of that forest. Each 10th of that forest is at various stages of growth from planting to Year 10. Overall, there is no net sequestration or release of carbon to the atmosphere, because I am harvesting at the same rate I am planting.

Agree that IF you can find a way to grow and harvest with low energy inputs, it would be a more desirable solution.

That is one hell of a big “if”, and they have been trying to resolve that since the 70′s. We hear time and again at how much more efficient algae is at harvesting sunlight, but that is meanginless if you can’t effciiently harvest the algae.

Turning corn into ethanol – for all it shortcomings- actually works, and has been easily scaled.

Algae to oil has yet to be shown to “actaully work” – meaning a remotely economic process, and it certainly hasn’t been done – economically or otherwise- at any large scale anywhere.

The reason why cron, soybeans, sugar cane etc are favoured is not the shallow root system or ability to grow in rows, it is that they;

produce a non cellulose product – oil or starch – that can *easily* be transformed into a liquid fuel

can be mechanically planted and harvested with relative ease.

Harvesting of fruit/nuts from perennial trees is much harder, and yields from year to year are more variable.

In addition, most GHG abatement plans hope to get carbon back out of the atmosphere, not just reduce how much is being added. Forests that are allowed to remain permanently uncut are the main way to do that.

It’s not quite that simple. Forests reach maturity, and the above ground biomass stops increasing at anywhere from 50 to 100 years. not only that, the on-ground biomass (deadfall) keeps increasing. In temperate, wet areas, the fungi decompose it to form soil/peat. But in dry areas (e.g. Canadian prairies) the deadfall builds up to where it is a major fire hazard, and the eventual fire returns all the above ground biomass to the atmosphere. In tropical areas (av temp>25C), the dead biomass hot composts and the CO2 is released anyway

So mature forests represent a carbon store, but only the temperate ones are sequestering carbon at any appreciable rate. Forests that have selective logging – while maintaing ground cover – will sequester more carbon as they fill in the gaps. If the removed trees are not burnt, then we have a carbon negative situation.

also for trees the overall photosynthethic conversion of solar light to biomass is low (<1 %)… whether you do grow corn or trees does not matter.

The soil use and fertilizer problems of landbased biomass practice seem to mee rooted in the fact that highly productive row crops like corn or soy are selected for small root systems so you can sow and grow more plants/square meter. I agree with the argument that deeper rooting systems like trees are much more sustainable.

Aquatic biomass and escpecially (single cell) algae and bacteria are much more efficient solarenergy harvesting.

1 There is no energy wasted on differentiation of complex stuctures like leaves or flowers.

2 The cells are submerged in water protecting the algae against UV light . lots of energy spent by landbased plants on dna repair due to UV induced damage.

3 the uptake of nutrients in algae is better, more surface to internal volume so the algae are better adapted to dynamics of sunlight. i.e single cells have a better way to deal with intensity fluctuations.

in relation to the statement that we burn in one year 400 years of stored solar energy: the size of the tap is important; if you look at the experiment of jan baptist the doubling time of trees is very slow compared to single cell based growth rates.

in contrast At some periods of year aquatic biomass like algae can achieve very high growthrates (biomass doubling times of hours are observed) and this is what lures many scientist towards the idea that algae can contribute significantly to fuel production. I am sceptic on many of the claims made by the algae guys but they seem to have a point here.

The tree biomass strategy only works out if we find ways to reduce al kinds of fossil energy use in a way that seems to me impossible to happen volunteerly.

“Rapid economic development means industrialisation, urbanisation, and motorisation. Over the next 20 years China and India combined (will) account for all the net increase in global coal demand, 94 per cent of net oil demand growth, 30 per cent of gas and 48 per cent of the net growth in non-fossil fuels.”

No, that’s not a typo. Let me repeat that: over the next 20 years, BP says China and India will account for 94 per cent of the net worldwide increase in oil demand.

No, that’s not a typo. Let me repeat that: over the next 20 years, BP says China and India will account for 94 per cent of the net worldwide increase in oil demand.

I have written pretty extensively about this in the book. This is why I argue that global warming is largely out of our hands. If you look at the growth rate for these country’s fossil fuel consumption over the past 10 years, that projection is entirely reasonable.

Aquatic biomass and escpecially (single cell) algae and bacteria are much more efficient solarenergy harvesting.

Agree that if you can find a way to grow and harvest with low energy inputs, it would be a more desirable solution.

One thing I meant to mention with the trees is that a tree plantation can have some net carbon sequestration over the short term. When the trees are harvested, they leave behind a root system that can take quite some time to decompose. So over the very long term it can be carbon neutral or close to it, over the short term it can be a carbon sink.

It’s not quite that simple. Forests reach maturity, and the above ground biomass stops increasing at anywhere from 50 to 100 years.

All forests sequester carbon. To maximize how much they sequester you have to let them reach maturity. At that point you have equilibrium. To sequester more carbon you have to expand forests …God forbid.

Harvesting brush and dead branches from dry forests susceptible to fires is reasonable but very labor and energy intensive and therefore not particularly profitable. The other option is to cut down the trees before they burn.

The carbon debt (how many years it takes to remove from the atmosphere the carbon added to it by “harvesting” a given ecosystem) can range from 10 years to a century, depending.

Point taken; large tree rootsystems as carbon sinks on the short term. natural ccs but i suppose it is minor compared to the amount of CO2 fixed in coral reefs…ocean surface is much larger compared to land surface. since you are stationed at an island i am always suprised you focus on trees;-)

The algae to fuel promise is indeed a big if, I have reasons to believe harvesting af algae can be done efficiently. the fact that landbased crops need to be planted mechanically and harvested is one of the reasons I think algaefarming has some advantages.

From my perspective (the Netherlands) transporting large wateflows is already daily practice to keep our feet dry (40 % of the country below sealevel…). Since we already manipulate large waterflows nationally I always argue that harvesting photosynthetic (algae)biomass from these vast amounts of water is an option to be implemented at significant scale. Of course largescale algaefarming requires proof at small scales where energy balances are skewed because of the dedicated pumps and harvesting equipment.

fossil oil only started to change the energy game in 1900′s when some smart geologists started to look and find oilfields that produced thousands of barrels/day by their own pressure.

This is how it works in practice. I have a forest that I will use to feed a BTL plant. Each year I harvest and replant 1/10th of that forest. Each 10th of that forest is at various stages of growth from planting to Year 10. Overall, there is no net sequestration or release of carbon to the atmosphere, because I am harvesting at the same rate I am planting.

Sequestration rates follow non-linear growth curves. Also, these charts represent three planting scenarios. Only one would fit your plan. A six inch seedling with a diameter of a pencil that grows for ten years will be ten to twenty feet high and the diameter of an arm or leg. And why wouldn’t an energy factory purchase its stock from third party suppliers and how do you control their behavior?

Fifty acres were harvested next to my forest property to make paper pulp because the trees were not big enough for lumber. They were also about the right size to feed to a power or liquid fuel plant. We all know what happens in a free market when demand rises. Turning forests into tree farms to power cars …don’t like the ring of that. There seems to be too much demand on forests already without adding fuel to the fire–was that a double entendre?

I’ve seen a few studies demonstrating that you will extract the most energy from a tree by simply burning it in place of coal to make electricity–very low tech and non-novel. The thought of powering my Leaf by burning farmed trees does not seem particularly ecologically sound, or appealing.

Yes indeed. But there is another way to sequester carbon, which is selective removal of trees from said forest. As in, not clear or block or strip cutting, but taking out trees here and there, such that the forest cover and ecosystem is maintained.

This guy on Vancouver island managed to do just that, and produced very high quality lumber along the way.

This is how it works in practice. I have a forest that I will use to feed a BTL plant. Each year I harvest and replant 1/10th of that forest. Each 10th of that forest is at various stages of growth from planting to Year 10. Overall, there is no net sequestration or release of carbon to the atmosphere, because I am harvesting at the same rate I am planting.

Sequestration rates follow non-linear growth curves. Also, these charts represent three planting scenarios. Only one would fit your plan. A six inch seedling with a diameter of a pencil that grows for ten years will be ten to twenty feet high and the diameter of an arm or leg. And why wouldn’t an energy factory purchase its stock from third party suppliers and how do you control their behavior?

We own our own forestry assets. I think that’s the only way you can ensure that it is done right. If you plant on a 7-10 year cycle you are taking advantage of the fastest rates of carbon accumulation. It is true that the diameter of the trees at that stage is only a foot or so, but if you are harvesting on that schedule you can plant them a lot closer together. So it is a model for sustainable energy and maximum accumulation of biomass per acre — if done correctly.

Russ said: We all know what happens in a free market when demand rises. Turning forests into tree farms to power cars …

RR said: So it is a model for sustainable energy and maximum accumulation of biomass per acre — if done correctly.

Finland does it correctly. Before Nokia, Finland’s main export was paper. Indeed, you can cut down all the trees today for short term profit, but somehow the Fins figured it out.

The problem is: are there any prostitutians left (or right) that think long term? When people start complaining that $4/gal is killing them, what will happen to long term planning.

The problem is political, as I see it. Back in the day good policy was used to limit the damage that unlimited capilatism would do. With lobbyists, revolving doors and SuperPACs, those happy days are long gone. Welcome to the modern era of slavery: you have been sold to the highest bidder.

Agree that IF you can find a way to grow and harvest with low energy inputs, it would be a more desirable solution.

That is one hell of a big “if”, and they have been trying to resolve that since the 70′s. We hear time and again at how much more efficient algae is at harvesting sunlight, but that is meanginless if you can’t effciiently harvest the algae.

Turning corn into ethanol – for all it shortcomings- actually works, and has been easily scaled.

An additional issue which has to be looked upon is the nature of the harvested algae i.e whether you want to identify the produce as a Biomass-feedstock or a lipid gunny sack. Cultivating algae as an alternative to land based cellulosic biomass has a major advantage of consuming less land area for cultivation. Secondly because the lipid content is no more of an issue, the algae productivities would be further ameliorated. Once dewatered and dried the algal biomass can be converted into pyrolysis oil which could be easily pumped to a central upgradation plant.

@ R.R: A good review with nice commentary & I especially liked the case study of Jan Baptist experiment. A supplementary article highlighting the differences between utilization of lignocellulosic biomass (e.g. wood) and herbaceous biomass (i.e grass) as potential feedstock’s would be a welcome addition.

Cultivating algae as an alternative to land based cellulosic biomass has a major advantage of consuming less land area for cultivation. Secondly because the lipid content is no more of an issue, the algae productivities would be further ameliorated. Once dewatered and dried the algal biomass can be converted into pyrolysis oil which could be easily pumped to a central upgradation plant.

Amen to that. The obvious starting place would be the Dead Zone in the Gulf of Mexico: clean up the environment free of charge while producing biofuels! This is the kind of research Uncle Sam should be subsidizing.

The other alternative would be to cultivate macro-algae, as these may be easier (or more energy efficient) to harvest.

Clayton Wheeler and his team in University of Maine introduced last October rathersimple technology (TDO). Do you have further data as this method could make fuelfrom papermill byproducts (bark, lignin) or sugarcane byproduct (bagasse) andeven from municipal waste. How does it compare with others like hot pyrolysis?